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Electronics => Repair => Topic started by: Daxxin on January 08, 2017, 10:00:43 am

Title: Agilent 16702 logic analyzer PSU fail
Post by: Daxxin on January 08, 2017, 10:00:43 am

PSU autec 552-1362A pcb rev. .X3  clicking wont start , any schematic beforte to check ?

Title: Re: Agilent 16702 logic analyzer PSU fail
Post by: bsalai on January 08, 2017, 11:33:37 am

Quote from: Daxxin on January 08, 2017, 10:31:31 am

Alredy replaced all diodes mosfet etc marked in the image

(https://s23.postimg.org/72heoef7f/image.jpg)



separated vertical module (i m the one broken the small cap ..isn't the cause of failure)
(https://s23.postimg.org/hdycuswaj/image.jpg)

I've not worked on this one, but I've solved a similar sounding problem in other power supplies in HP scopes by removing the electrolytic capacitors, cleaning the PC board under them (even if you don't see anything, and installing new caps. Apparently some of the caps leak.
Good luck.


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Title: Re: Agilent 16702 logic analyzer PSU fail
Post by: mos6502 on January 08, 2017, 04:07:54 pm

Clicking means that some protection circuit is active, either overcurrent or overvoltage. You need to trace the circuitry going to the control pin of the TOPSwitch and see what is making it stop. Randomly replacing parts is unlikely to result in success.

Title: Re: Agilent 16702 logic analyzer PSU fail
Post by: Daxxin on January 15, 2017, 02:51:08 pm

Tried to draw schematic from board , maybe there is errors , got short SCR1 , SCR2 and D3
5 modules input 300Vcc

(https://s28.postimg.org/clcys70q3/PSU.jpg)

(https://s29.postimg.org/8q29quayf/20170115_183909.jpg)